Our plan the first day was not to kill the beast but to follow him, to observe his home and habits, to see the evil that he did and maybe get in his face.

For this, Sonny took me to Maunawili, a neighborhood tucked beneath the razor-ridged Koolau mountains on the windward side of the Hawaiian island of Oahu. He parked his truck at a house at the forest’s edge, put on camo gear and boots and backpack, and led me to a path behind the swimming pool that plunged into the jungly green.

The bright sun gave way to dappled darkness. Octopus trees, their rubbery leaves splayed on umbrella spines, wild ginger, thick-trunked avocado and mango trees, a lush understory of ferns and pili grass — we were in a classic Hawaiian wilderness, but a damaged one.

Sonny pointed out the signs: the erosive trails the beast had trampled, the ravaged stream banks and fields of blackened muck he had nuzzled and plowed with bladelike tusks, looking for roots and worms.

We saw his muddy wallowing spots. We saw droppings. We saw cloven hoofprints — his own and the tiny pairs of dots, incongruously dainty, left by his abundant and ravenous spawn.

Under a towering avocado tree, Sonny stopped. He held a finger to his lips.

We stared across at a low thicket of ferns. The fronds swayed and shuddered, and I caught a glimpse of a splotch of darkness that could have been a shadow or the black bristling snout of feral boar.

We waited. We soon realized the boar had melted back into the underbrush.

Pursuing pigs

Sonny Thater, a licensed fishing and hunting guide, is a professional pig eradicator, on call for homeowners and businesses with nuisance pigs, and for tourist hunters looking for an unusual trophy. I had found Sonny online, at hookyouupoutfitters.com.

He is one of many in Hawaii who grew up hunting pigs, an old family tradition that dates at least to the islands’ plantation days of the early 20th century. Sonny is one of the very few who have made a business of it. He is thickset and wears his hair in a bristle cut, yet even when dressed head to toe in camo and holding a bayonet, he looks gentle, like someone who’d bring you coffee and doughnuts if you asked.

Everybody knows that the Hawaiian Islands are an imperiled Eden, a global hot spot for threatened and endangered species. But even though I had grown up there, I had never done much to help it, until I thought of a way to do my part: Go there and kill some pigs. It seemed like a righteous mission, and Sonny was going to guide me.

The story of the Fall is this: Somebody in the Garden eats what he’s not supposed to and messes things up for everybody else. Hawaii’s hospitable habitat has long been overrun by opportunistic outsiders: feral sheep, feral goats, even feral cows, along with mongooses and exotic birds. Hoofed livestock, brought by Europeans, has done the most damage (once they escaped and moved into the wild).

With their boundless appetites and unchecked fertility, Eurasian feral pigs, Sus scrofa, are the worst of the worst. These are not the little Asian domesticated pigs that Native Hawaiians farmed for centuries, but descendants of the big European swine that started getting loose and going native after Capt. Cook put Hawaii on the map in 1778.

“They rototill the planet,” Dr. David Duffy, a biology professor at the University of Hawaii, told me. On my visit earlier this year, he and Dr. Thane Pratt, an authority on Hawaiian forest birds, explained the problem. Feral pigs eat native plants and, through their scat, spread invasive ones like the forest-clotting strawberry guava. Indirectly, they slaughter birds — the stagnant, mucky wallows they dig breed mosquitoes that carry the bird-killing avian malaria.

Their only redeeming trait is that they are delicious, which was the other reason that two days after our Maunawili probing expedition, Sonny took me out for the kill.

We had hooked up with members of the Pig Hunters Association of Oahu — Miles, Greg, Eddie, Boomer, Buddy, Dakota, Duke, Max, Miracle, Rascal, Shadow and Spunky — and well before sunrise on a Friday, we headed to their favored hunting grounds in Halawa Valley.

Miles Fukushima and Greg Tanaka have hunted together for years, and now that they are retired from their day jobs — Miles drove a garbage truck and Greg delivered the mail — they go out twice a week, every week, for pigs.

The other members of the group were dogs, mostly variations on Rhodesian ridgebacks, Miles said. They rode in a cage in the back of Miles’ pickup, stuffed in like commuters on a rush-hour train, all business on their way to work.

The Hawaiian pig-hunting method uses dogs, not guns. Dogs and knives. The dogs chase the pig; you chase the dogs. The dogs pin down the pig, which you finish off with the knife. This method is considered safer than shooting (stray bullets on tiny, crowded islands: no good) and more reliable, since pigs are cryptic, elusive and very smart. Good dogs with good noses give human hunters the edge they lack.

I am not an animal killer, except for fish, and the thought of close-quarters combat with a tusked mammal almost my size gave me pause. Miles and Sonny told me how: Grab the pig’s left hind leg with your left hand and hold on, while using your right hand to introduce the blade behind the shoulder, into the heart. “Don’t do the ‘Psycho’ thing,” Sonny said. “And watch out when he jerks his head back to bite your hand off. Don’t take the knife out.”

I decided I had to do it — it would be an exercise in ecological balance, a small act to help save little forest birds from extinction. When the moment came, I imagined, I would take no pleasure in it but just do my job, perhaps whispering into the pig’s ear: “This is for the ‘o’o bird. The mamo. And the po’ouli. Aloha, bruddah.”

Perhaps then the pig would grasp the horror — the horror — of what its species had done. That was the plan. It did not work out that way.

On the hunt

We walked in single file along a stream, and I soaked in the scenery, recalling the pleasure that hiking in Hawaii gives. Its forests have no scary reptiles, no vicious poisonous plants; the only real hazards are mosquitoes and slippery streambeds. And Halawa is a valley of staggering beauty. We passed stands of wild orchids and a colossal breadfruit tree.

We found remains of an old stone wall. We found trash left by other hunters. We found pig tracks and trails. What we didn’t find was a pig. All day the dogs remained mostly quiet and calm, poking around for a boar they couldn’t find. I went home with no pig, but memories of a lovely hike.

Sonny felt so bad that he gave me a mess of pig from his freezer: ribs and tenderloin. The tenderloin became Hawaiian kalua pig, oven-roasted with rock salt; Okinawan rafute, boiled with sake and soy sauce; and adobo, Filipino stew with coconut milk. I made a feast for my family and ate to ease my dejection.

“I wish you had been here last week,” Sonny said. Or the next. The following Friday, he took out a client from Canada named Rylan. The dogs found a boar, chased it into the streambed and Rylan stabbed it. He carried it home, piggyback.

Sonny texted me photos of Rylan with his trophy, all huge tusks and reddish bristles. One more pig down, I thought. Many, many more to go.